1. Field of the Invention
The present invention relates to a device for regulation of the tapering of the side edges of a package of yarn in a textile winding apparatus, wherein a pakcage of yarn is provided on a spool, making the latter to rotate around its own longitudinal axis, while at least a yarn guide member, moving reciprocally and parallel to said longitudinal axis of the spool, distributes said yarn onto the spool itself.
2. Description of the Related Art
In winding apparatus knon hitherto, the tapering of the side edges of the package of yarn, in other words the conicity of said side edges, is achieved by gradually shortening the stroke of the yarn guide member as the deposit of yarn on the spool increases.
Currently, this variation in the stroke of the yarn guide members can be obtained by using a single cam contour attached to the axis of the spool-holder arm which, via a suitable transmission mechanism, drives the variation of the stroke of the yarn guide members. With this known device, when it is necessary to vary the profile of the side edge of the package of yarn, the cam for driving the stroke of the yarn guide member has to be replaced. It is therefore necessary to stop the machine and replace said cam with another cam having a more suitable contour for the type of work in progress. This changeover obviously involves costs, both due to the use of labour to perform said operation of replacing the cam, and due to the nonproduction caused by the down time of the machine for performing the change of the cam.
Some manufacturers have decided to solve the previous problem by setting up a cam having different contours for different taperings of the side edges of the package of yarn. Said contours are formed in a series along the same circumferential line of the cam, i.e. on the edge of a same discoidal element forming the cam. The median lines of all said contours of the cam lie on the same plane. In this way the operation of removing and replacing the drive cam contour is made easier. In fact it is sufficient to rotate the discoidal element and place the required cam contour in the working position. However, the use of this type of drive cam has disadvantages; it is in fact necessary in this case also to disengage the discoidal element which holds the cam contours from the spool-holder arm to make it rotate, position and re-engage it in the required working position. These operations also require a certain working time by stagg and the machine has to be stopped.
Moreover this cam element is limited in the number of cam contours which it can hold or in the angle of rotation which these contours can achieve. In fact, if for example four cam contours are used, each of these can at most rotate through ninety degrees.